Open to senior & staff roles · Remote
> Senior Full Stack Engineer, AI Engineer, Platform architect, Payments systems builder
I'm Hank Coleman, a senior full-stack and AI engineer with eight years of designing, shipping and running products end to end: React frontends, APIs, payment ledgers, multi-tenant platforms and LLM features backed by evals. I lead the design, write the code and stay on call until it's boring.
const hank = {
role: "Senior Full Stack & AI Engineer",
experience: "8+ years",
focus: ["full-stack products", "AI features", "payments"],
stack: ["TypeScript", "React", "Go", "Python", "Postgres"],
replies: "within 24h",
available: true,
};01About
Who I am
I do my best work on systems where a bug costs real money or real trust. I start with the invariants (what must always be true), design the data model around them, and only then worry about speed.
Senior work is mostly leverage. I write the design doc that ends the debate, build the template the next ten services start from, and turn engineers into owners. I cut scope hard so the important part ships on time.
At a glance
Available now
how-i-work.ts
const workingStyle = {
invariantsFirst: true,
designDocs: "before code",
onCall: "until it's boring",
mentoring: true,
};Correct first, then fast.
Invariants, idempotency and tests that encode business rules come before any optimisation.
Boring technology, used well.
Postgres, a queue and plain HTTP solve most problems when they're designed carefully.
Ship the metric with the feature.
Every project launches with the number that says it worked, and an alert for when it stops.
Write it down.
Design docs, ADRs and runbooks, so decisions outlive the meeting they were made in.
02Selected work
Each case study covers the problem, what I owned, the decisions that mattered and the numbers afterwards. Start with the flagship.
Customer balances were computed by nightly batch jobs that drifted from the payment processor. I led the design and rollout of a real-time ledger that now backs every balance in the product, with zero drift since launch.
Tech leadRead case study
An in-house authorizer that approves or declines every card payment in under 50 ms, with in-line fraud scoring and a safe degraded mode.
Tech leadRead case study
A zero-downtime, strangler-fig migration of a nine-year-old monolith across three product teams.
ArchitectRead case study
A retrieval-augmented assistant that drafts cited answers for support agents, gated by evals in CI.
Lead engineerRead case study
Warm-standby disaster recovery for a payments platform, with a one-command failover rehearsed every quarter.
Lead engineerRead case study
One permissions service and enterprise SSO for a SaaS product whose access rules lived in 14 codebases.
Tech leadRead case study
Unified tracing, metrics and SLO alerting across 40+ services, so pages mean something again.
Senior engineerRead case study
A 41% cut in AWS spend with no loss of reliability, by making cost visible to the teams who create it.
Program leadRead case study
A marketplace storefront rebuilt on server rendering, with performance budgets enforced in CI.
Frontend leadRead case study
Product search rebuilt with typo tolerance, facets and learning-to-rank on click data.
Backend engineerRead case study
03Experience
Eight years, with scope growing from features to systems to the platform other teams build on.
Fintech scale-up · Series C · payments and card issuing
Tech lead for core money movement: the ledger, payment APIs and their on-call.
B2B SaaS platform · Workflow software · 2,000+ business customers
Platform and infrastructure, then architect for the monolith migration.
E-commerce marketplace · Consumer marketplace · 4 locales
Search and storefront teams.
Digital product studio · Agency · startup and enterprise clients
Full-stack delivery across a dozen client products.
04Stack
Deep in a few core technologies, and quick to pick up whatever the problem needs.
05Contact
Open to senior and staff roles, and selected contract work.